Manhole structure for truck tanks



Aug; 25,1942.- o. N. @REBEL-L A 2,294,175

MANHOLE STRUCTURE FOR TRUCK TANKS Filed opt. 1v, 193e '4 sheetssnt 2 /0 INVENToR f 23 EQI 0 /V @ren/ ll 1` ATTORNEY 118225,71912.- o. N. cam-:DELL 2,294,176'

MANHOLE STRUCTURE FOR TRUCK TANKS Filed 6st., rr. 193s 4 suma-sheet s ,I #113, 4. I7 l l 8 l 46 0 49 40 39 l 4f 5^ 4 I y 4.3/ 3, 2 I l 44 i6 if zo I 6/ J? 67 0 4 f I l 6* l 77 I 756 6d 92 7 7/ ,5`

l A 2 2/ l 22 i? 3 W lf 63 7s 62 l/ 3 y 7; 8 l if 2,0 f4 7 9 v9.5 84 4 47 43 s? 45' ,o V l f 4 if g 66 6 75 7 a f 0 Z2 l "x @u 2' i? "E5 62 i; 155 9" s2 55 i 3 L" if? /s ,lNvlToR 23 0f 1 ATTORNEY .4275, 1942. o. N. GREDELL 23945176 MANHOLE -STRUCTURE FOR TRUQK TANKS Filed ocu-1?, 1958 A4 sheets-snuit. 4

INVENTOR 0f o /V Grade/Z m Patented Aug. 25, 1942 UNITED STTES PAINT OFFICE MANHOLE STRUCTURE FOR TRUCK TANKS Application October 17, 1938, Serial No. 235,412

4 Claims.

This invention relates to manhole structures particularly those employed in truck tanks, and has for its principal objects to provide a manhole structure of this character with a quickly detachable cover; to provide a cover secured by spring loaded locking levers that firmly clamp the cover to its gasket seat but which are yieldable to allow raising of the cover under excessive tank pressures; to provide uniform clamping action of the cover von the gasket at all times; to provide a cover clamping mechanism which automatically compensates for wear and changes in the gasket due to compression or temperature variations; and to provide a cover clamping mechanism designed to eliminate sparking hazards.

Other objects of the invention are to provide the manhole structure with a bottom ll loading device thereby avoiding agitation of the liquid upon lling of the tank with resultant loss of vapors; to provide the manhole structure with a gauge marker adjustably attached and sealed to the manhole collar; and to provide a gauge stick guide.

In accomplishing these and other objects of the invention, as hereinafter pointed out, I have provided improved details f structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a fragmentary sectional View of a truck tank equipped with a manhole structure embodying the features of the present invention.

Fig. 2 is a plan view of the manhole structure showing the iill cover broken away to expose the bottom filling member.

Fig. 3 is a vertical section throughthe upper part of the manhole structure on the line 3-3 of Fig. 2.

Fig. 4 is a vertical section taken at right angles to the section illustrated in Fig. 3.

Fig. 5 is a detail section through one side of the manhole structure particularly illustrating one of the cover locking levers.

Fig. 6 is a similar view showing the locking lever in released position. t

Fig. 7 is a detail perspective View 0f one of the locking levers.

Fig. 8 is a section through one of the locking levers particularly illustrating mounting of the clamping hook.

Fig, 9 is a detail perspective View of the upper end of the bottom iill member.

Fig. 10 is a perspective view of the seating ring on the manhole structure for centering the fill member.

Referring more in detail to the drawings:

I designates the shell of a conventional truck tank forming a liquid carrying compartment 2 to which access is had through an elongated manhole opening 3 in the top of the tank. The opening 3 is encircled by a collar 4 having an upper peripheral edge 5 projecting slightly from the top of the tank and a lower portion 6 depending into the tank and forming a support for a bottom closure cap l. The cap 'I includes an annular wall 8 slidable over the depending portion of the collar and has a bottom 9 provided with a central opening I0. The opening I is encircled by a ring II attached to the bottom 9 by suitable fastenings, such as rivets I2, and is provide-d with an annular rib' I3 terminating in an inwardly and downwardly inclined seating flange I4 for a purpose later described.

The cap 'I carries attaching clips I5 spaced from the upper edge thereof and having inwardly directed ears IB provided with slots II to accommodate the threaded Shanks I8 of J-bolts I9. The hook ends of the J-bolts are engaged in openings 20 of the manhole collar so that the Shanks thereof swing into the slots and are retained by wing nuts 2I threaded thereon. The cap is thus adapted for removal by loosening the wing nuts and withdrawing the shanks of the J-bolts from the slotted ears while the hooked ends thereof are pivoting in the openings 20. The cap may then be pushed downwardly until it clears the lower edge of the collar, thereupon it is turned through an arc of tilted sidewise, and withdrawn through the collar.

Centered by the ring Ii and seated within the flange I4 thereof is a funnel-shaped inlet 22 of a bottom lling tube 23. The tube 23 depends to a point slightly above the bottom of the tank and has arms or straps 24 spacingly carrying a socket 25 formed in the apex of a bell-shaped guide 26 whereby the socket 25 is guided into engaging relation with a center pin 2l carried on a bracket 28 attached to the bottom of the tank. The lling tube is retained in seated engagement Ywith the centering ring and with the socket engaging the pin 2l by a clamping device 29.

The clamping device 29 includes a rod 33 pivotally anchored at its lower end to ears 3| attached to the bottom 9 of the cap 'I and which has a head 32 formed on its opposite end and engaged by a spring 33 that is sleeved over the rod and has its opposite end bearing against an inturned flange 34 of a tube 35. The tube 35 is slidable over the spring and carries a hookshaped head 36 engageable with the rim of the funnel-shaped inlet. The hook-shaped head has a hook 31 adapted to be engaged by the finger of the operator in compressing the spring 33 and raising the hook 3e over the rim of the filling member.

Mounted on the rim of the manhole collar is a manhole cover 39 of sulicient size to accommodate a groove 48 containing a compressible gasket ring 4I which seats upon the edge 5 of the collar. The cover` also includes a flange 82 telescopingly movable through the upper end of the collar and which is connected by radial ribs 43 with a flange 43 encircling a ll opening 48 through which the tank is filled by way of the bottom filling tube. The ll opening is encircled on the exterior side of the cover by a rib 45 forming a seat for a compressible gasket e6 carried within an annular groove 41 on the under face of a fill cover 48. rIhe fill cover 88 is hinged to one side of the manhole cover as indicated at 49 and is latchingly retained by clamping lugs 58 and 5I engaging wear plates 52 attached to the flange 83. The lugs 5I and 52 are retained on operating shafts 53 and 5Li journalled within stuing boxes 55 and 5S in the fill cover as best shown in Fig. 3. The shafts are actuated to move the lugs to and from locking engagement by handle levers 51 and 58. The lugs are also interconnected by segmental gears 59 and 69 having intermeshing teeth 6I so that the lugs may be operated by either one or both handles.

The fill closure briefly described forms no part of the present invention but is covered in and fully described in Patent No. 2,031,885 granted to applicant under date of February 25, 1936.

The manhole cover is clampingly locked to the collar in such manner that it is adapted for quick release and is arranged to be automatically raised in case of excessive pressure as in the instance of re occurring about the tank.

The clamping mechanism includes a plurality of spring loaded locking levers B2 arranged at spaced intervals about the inner periphery of the collar and which are best illustrated in Figs. 5 to 8 inclusive. The locking levers include inwardly extending hook-shaped handles 63 and outwardly extending heads 8G. The heads 84 have slots 65 to accommodate the swivel ends 68 of expansion springs 81. The swivel ends 68 terminate in eyes 88 located within the slots and engaging the transverse pins 89 extending through the levers and through the eyes as best shown in Figs. 6, 7 and 8. Projecting from the sides of the levers and spaced on the side of the pins 89 opposite the handle are studs 19 and 1I carrying clamping hooks 12. The clamping hooks are formed in mated sections 13 and 14 having wings 15 provided with bearing openings 15 engaging the studs and retained thereon by peening or riveting over the projecting ends of the studs as indicated at 11. The sections of the hooks also include inwardly extending abutting flanges 18 and 19 carrying hooks 89 and 8| that are secured together by a rivet 82. The hooks have notches 83 spaced from the iianges 18 and 19 to freely accommodate and engage the lower edge of the manhole collar as shown in Fig. 6. The peening of the studs is such as to slightly bind the wings on the trunnions so that the hooks will move with the levers 63 when they are pivoted on the eyes of the springs. The upper ends of the springs 81 have hooks 84 engaged in openings in the ribs 43 previously mentioned.

In order to indicate maximum capacity of the tank the manhole collar carries an inwardly extending bracket having ears 86 and 81 rotatingly supporting a threaded screw 83. The screw 88 has a head 89 engaging the lower ear and an upset end 90 engaging the ear 86. Threaded on the screw and having a flat face portion 9| engaging against the bracket is a pointer 92. The pointer 92 is adjusted vertically with respect to the depth of the tank by rotating the head of the screw until the pointer is at the correct level indicating the predetermined maximum capacity of the tank, whereupon a strand 93 is passed through openings 94 in the head and 95 in the ear 81 and the ends connected by a seal 95. Bolted to a boss on the bottom of the cover is a gauge stick guide loop 91 cooperating with an aligning opening 93 in the bottom of the cap 1 to guide the measuring stick to a predetermined location in the bottom of the tank.

In assembling the manhole structure, the cap 1 is passed through the manhole collar and moved in telescoping engagement with the lower edge of the collar until stopped by the clips I5. The J-bolts I9 are then applied with the hooks engaging in the opening 28 and the pins passed through the slots I1. The wing nuts are then tightened against the slotted ears of the clips to securely retain the cap relatively to the manhole collar. The bottom fill member is then inserted through the centering collar until the guide 25 engages the pin 21, whereupon the socket 25 is moved into engagement with the pin to securely retain the lower end of the fill member. When the fill member is in position the funnelshaped upper end thereof wedgingly engages the seating flange I4 of the centering collar. The clamp 29 is then moved into hooked relation with the rim thereof as shown in Fig. 3. The manhole cover 39 is applied to its seat on the peripheral edge 5 of the collar 4 in such a manner that the levers 62 depending from the springs 61 pass through the collar. The operator then opens the ll cover and reaches through the iill opening to grasp the handle 63 of one lever by which he steers the hooks 88 and BI of the hook member 12 into hooked relation with the bottom edge of the manhole collar, the hooks passing through a slot 99 in the wall of the cap 1. The lever is then swung downwardly with the studs pivoting within the bearings 16 on the wings 15 to tension the spring 61. By the time the end of the lever has engaged the wall of the cap, the pin 68 has passed bottom dead center relatively to the axis of the studs so that the loaded springs draw the gasket tightly against the seating edge of the manhole collar and retain the clamping hooks 12 in engagement with the opposite edge. lThe other levers are then manipulated in like manner. The compartment of the tank is then filled through the iill opening with the liquid passing through the iilling tube to the bottom of the tank. The liquid gradually rises in the tank until it reaches the predetermined level as indicated by the pointer. The filler cap is then swung to closed position and locked by manipulation of the handles 51 and 58.

Should excessive pressures occur in the compartment of the tank, as in the instance of a lire, the pressure acts against the bottom of the manhole cover and lifts it from seating engagement with the collar against action of the loading springs. When the pressure is relieved the springs return the cover to seatedY engagement to prevent further loss of vapor.

Attention is directed to the fact that the springs retain the gasket in uniform clamping contact about the periphery of the collar regardless of expansion and contraction due to change in the temperature or change in the shape of the gasket.

From the foregoing it is apparent that I have provided a manhole cover which is of simple construction and capable of being quickly removed and reapplied without the aid of wrenches or the like.

What I claim and desire to secure by Letters Patent is:

l. In an apparatus of the character described, a manhole collar having a circumferential seat, a manhole cover engaging said seat and having a fill opening therethrough, coil springs having one of their ends xed to the manhole cover and having their other ends adapted to depend freely within said collar, lever arms pivctally suspended from the free ends of the springs and accessible through said ll opening, and hooks pivotally connected to and carried by the lever arms and adapted to be steered by the lever arms into hooking engagement with the manhole collar, said hooks forming fulcrums for said lever arms when the lever arms are pivoted relatively to the hooks for loading said springs to yieldingly retain the manhole cover, said pivotal connections between the lever arms and the springs being arranged to be carried past dea-d center position with respect to the pivotal connections between the hooks and said lever arms for locking the springs in said loaded position, said springs being yieldable under a predetermined pressure acting on said cover for releasing excess pressure.

2. In an apparatus of the character described, a manhole collar having a circumferential seat, a manhole cover engaging said seat and having a fill opening therethrough, coil springs having one of their ends fixed to the manhole 4cover and having their other ends adapted to depend freely Within said collar, lever arms pivotally suspended upon the free ends of the springs and accessible through said fill opening, hooks pivotally connected to and carried by the lever arms and adapted to be steered by the lever arms into hooking engagement with the manhole collar, said hooks forming fulcrums for said lever arms when the lever arms are pivoted relatively to the hooks for loading said springs and to carry the pivotal connections between the lever arms and the springs past dead center position with respect to the pivotal connections between the hooks and said lever arms to yieldingly retain the manhole cover on said seat, said springs being yieldable under predetermined pressure acting on said cover to relieve excess pressure, and means associated with the manhole collar and having guide means to facilitate guiding of the hooks into engagement with the manhole collar and to prevent turning thereof upon manipulation of the lever arms.

3. In an apparatus of the character described, a manhole collar having a circumferential seat, a manhole cover engaging said seat and having a iill opening therethrough, coil springs having one of their ends fixed to the manhole cover and having their other ends adapted to depend freely within said collar, lever arms pivotally suspended by the free ends of the springs and accessible through said fill opening, and hooks pivotally connected to and carried by the lever arms and adapted to be steered by the lever arms into hooking engagement with the manhole collar, said hooks forming fulcrums for saidl lever arms when the lever arms are pivoted relatively to the hooks for loading said springs and to carry the pivotal connections between the lever arms and the springs past dead center position with respect to the pivotal connections between the hooks and said lever arms to yieldingly retain the manhole cover on said seat, said springs being yieldable under predetermined pressure acting on said cover to relieve excess pressure.

4. In an apparatus of the character described, a manhole collar having a circumferential seat, a manhole cover engaging said seat and having a ll opening therethrough, springs having one of their ends Xed to the manhole cover and having their other ends adapted to depend freely within said collar, lever arms swivelly and pivotally carried by the free ends of the springs and accessible through said ll opening, hooks pivotally connected to and carried by the lever arms and adapted to be steered by the lever arms into hooking engagement with the manhole collar, said hooks forming fulcrums for said lever arms When the lever arms are pivoted relatively to the hooks for loading sai-d springs and to carry the pivotal connections between the lever arms and the springs past dead center position with respect to the pivotal connections between the hooks and said lever arms to yieldingly retain the manhole cover on said seat, said springs being yieldable under predetermined pressure acting on said cover to relieve excess pressure, and means associated with the manhole collar and having guide means to facilitate guiding of the hooks into engagement with the manhole collar and to yprevent turning thereof upon manipulation of the lever arms,

OTTO N. GREDELL. 

